Adding pre-fill. Editorial

diff --git a/lsp-misc/misc.lsp b/lsp-misc/misc.lsp
index 9e77db93efe06db5c81e050265abcc7f3dd561b7..ff76d5a294b8dfd6b3e1da5e3e3669d4ae8d1429 100644 (file)
--- a/lsp-misc/misc.lsp
+++ b/lsp-misc/misc.lsp
@@ -1,3 +1,5 @@
+;; This module provides some global utility functions.
+
 (define (prog1 X) X)
 (global 'prog1)
 
@@ -6,8 +8,14 @@
   (and N (exit N)))
 (global 'die)
 
-(define (char2hex STR)
-  (join (map (curry format "%2x") (map char (explode STR)))))
+;; Prepend with C onto S so as to fill width W, if it's a number.
+(define (pre-fill C S W)
+  (if (and (number? W) (> (setf W (- W (length S))))) (string (dup C W) S) S))
+(global 'pre-fill)
+
+;; Make a hex string from a data block pad with "0" to W if non-nil
+(define (char2hex STR W)
+  (pre-fill "0" (join (map (curry format "%2x") (map char (explode STR)))) W))
 (global 'char2hex)
 
 ;; Print binary byte as octal or as ASCII character [32-126]
@@ -20,12 +28,12 @@
   (join (map octal-byte (unpack (dup "b" (length S)) S))))
 (global 'octals-string)
 
-;; Return byte code as printable or as code.
+;; Return byte code as printable or as decimal number.
 (define (human-byte B)
   (if (and (> B 32) (< B 127)) (char B) B))
 (global 'human-byte)
 
-;; Return a packed encoding of a list of bytes, joining string elements
+;; Return a packed encoding of a list of bytes, joining its string elements
 (define (human-bytes BL)
   (let ((OUT '()) (X nil))
     (dolist (B (map human-byte BL))